People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

Florida fisherman Tom Rigby knew there was something interesting on the end of his line after a 20-minute fight on the Phillippi Creek in Sarasota. When he finally reeled in his prize, he was surprised to find a row of human-like teeth in the mouth of a fish he had never come across before. After taking a picture of his catch and releasing it back into the water, Rigby went on with his Memorial Day weekend fishing trip. He would later find out he unknowingly released the South American Pacu, more commonly known as the "testicle-eating fish."

“I had the drag set pretty tight, and it's running with it,” Rigby told WWSB MySuncoast. “My first thought was a jack because they fight like crazy. I got out my fish ID chart and go through all of the species. I can’t see anything that looks like the species. I'm looking at all of the teeth, saying this thing can do some serious damage to another fish or something. I found out it has a reputation for going after men’s testicles. I was just worried about it biting my finger.”

According to the Florida Fish and Wildlife Conservation Commission, the Pacu is a close relative to the Amazonian piranha that can reach up to 3 feet and 55 pounds in the wild. A large number of Pacu have been pulled from Florida waters due to their popularity among people in the aquarium industry. Reports of piranha in Florida usually turn out to be its much larger cousin with a nasty reputation for biting down on men’s private parts.

With its relatively close proximity to South America, finding the Pacu in Florida waters may not seem that outlandish, but all the way up in Michigan? Detroit resident Holly Luft and her husband Tom did not expect to find a 14-inch Pacu on the end of their line while fishing in Lake St. Clair between Michigan and Ontario, Canada. The Michigan Department of Natural Resources confirmed the catch and said the fish was probably released from a local aquarium after it grew too large and hostile.